That all depends on what you want in your tank. Tank, filtration, powerheads, possibly a skimmer, liverock, live sand, lighting and livestock. We have to know what it is you want to do with your tank exactly? But welcome and enjoy!

Ah, but what kind of corals? Softies, LPS, SPS? The primary determining factor there is lighting. Most recommend at least 1-2 lbs rock per gallon, so I'd aim for at least fifty pounds. A good way to cut costs is to get mostly dry base rock and add a few pieces of live rock to seed the system. Just take it slowly! Nothing good happens fast in this hobby! Melosu58 mentioned the articles, and there are some really great ones on this site.